Reference karyotype of H. irritans with 2n=10. a Giemsa stained C-banded mitotic metaphase from larval brain; arrow indicates satellite on chromosome 3, sc: secondary constriction b Idiogram of the C-banded haploid set c Hoechst 33258 stained H-banded mitotic metaphase from larval brain d Idiogram of the H-banded set e–f Orcein stained meiotic metaphases II from testis; both figures were observed in the same individual. a, c, f arrow indicates satellite on chromosome 3. sc: secondary constriction on chromosome 2.